This paper investigates the cooperative communication system with untrusted relay using the new scheme that the source transmits the jamming signals and the source signals at the same time. We exploit greedy power allocation algorithm to divide the source power to ensure maximum secrecy capacity. Besides, we analyze the situation that external eavesdropper and untrusted relay exist at the same time. At the end of the paper, BPSK modulation and demodulation scheme is given as an example, and SER… CONTINUE READING